An extremely common sight when you’re in the rural area is a turbine-blade-like object rotating in a circle every now and then. That is called a weather vane, or wind vane, as some call it.
Most commonly, weather vanes have either an animal or an arrow to point at a direction.
A little observation would tell us that these weather vanes serve a pretty straightforward purpose. It tells us the way the wind is blowing. But that’s not always the case, as you’ll find out in this article.
Let us delve deeper into this thousand-year-old invention. We’ll find that the relevance of a wind vane is never going to go away.
What Is a Weather Vane?
A weather vane is an instrument used to determine and point to the direction of the wind. It’s typically hoisted at the highest point of a building to catch the most unobstructed wind.
Despite it being invented for determining wind direction, it has been used just as an architectural ornament on large buildings.
Look up Bishopsgate on Google images, you’ll find a beautiful golden beaver design on the weather vane.
Then, we have a golden grasshopper on top of the Royal Exchange building, the previous center of London’s trade. There are so many weather vanes around the world just like them.
Who Invented The Weather Vane?
Weather vanes are one of the oldest inventions dating back to 48 B.C. It was Andronicus, a Greek astronomer, who designed it as a tool to determine the wind direction. Almost 2,000 years!
The first weather vane had the Greek god Triton as its design, who had the body of a man and the tail of a fish. It was positioned at the Tower of the Winds.
Coincidentally, the Chinese also started using weathervanes at the same time period.
The history is long and beautiful. Maybe another time!
What Is the Design of a Wind Vane?
Weather vanes have a head and a tail in their design. Often you’ll see them having a rooster-shaped design. In this case, the beak of the rooster is the pointer, and its tail is the vane’s tail.
Whichever the object is used on a weather vane, it’s positioned on a pole in a way that it’s free to move in any direction. It is allowed to rotate around its vertical axis.
You’ll also notice weather vanes have a pair of letters such as “N, E” and “S, N” on another straight rod. These are called directional letters.
Some might even have all of 4 them pointing towards the 4 directions. This will make it easy to recognize the direction of the wind much faster. It’s clear that this is a modern design, in the old days; people didn’t need any pointers to know which direction is what.
Unfortunately, we’ve lost touch with the sense of direction. So, we can’t but rely on the help of directional letters.
When there are 2 directional letters, how are the direction letters set? This has to do with the specifics of a region. If a region has a dominant wind direction, then the letters of that direction and its opposite is used on the directional rod.
How Does a Wind Vane Work?
Weather vanes have a fairly simple mechanism. Any junior school student can grasp the idea. As mentioned before, weather vanes or wind vanes have a head or a tail as part of their design, and those are the working parts.
The tail has a particular design with a large surface area. No matter what the object is used, it’s made sure that it’s big enough to catch the wind. On the flip side, we have the pointer or head element that’ll simply point towards the direction of the wind.
This is how it works:
The wind hits the tail propelling it or forcing it to rotate around its vertical axis. It’s pushed to a position where the tail’s large surface area is parallel to the direction of the wind. And that means the wind cannot force the vane to rotate anymore.
At that point, the head will be facing towards the opposite direction. This is the direction from which the wind is coming from while the tail of the arrow/animal is pointing to the direction the wind is going towards.
For instance, the arrow or the mouth of the animal is facing towards the north. In this case, it’s experiencing a northern wind that is southbound. It means the wind is blowing from the north and going to the south.
Different Types of Wind Vane
Weather vanes have a lot of names, such as wind vane and weathercock. And there are different types of wind vanes as well. Modern wind vanes have some of the most beautiful designs.
There are different wind vanes such as Weather Vane, Wind Sock, and Digital Wind vane. Although the underlying principle is one and the same, the difference in their purpose and design is very apparent.
This is the weather vane that’s been here for centuries. You can find them in the rural areas even nowadays set up on top of barns, houses, churches, cathedrals, etc.
These weather vanes have only two purposes. Either they are used to determine the wind direction or they have used a decorative piece of a building (with the wind direction determining feature).
This ancient type of weather vanes is the one with silhouettes of different animals. Some might also have silhouettes of different persons, ships, or fishes. Most of them only have an arrow as the wind vane.
Then we have a modern revision of the original weather vanes, a windsock. Windsocks have a completely opposite design. And it’s not used to determine the direction of the wind. You probably have seen them in airports. It’s the one with orange and white stripes that reminds you of a street/construction cone.
It doesn’t have any tails or heads or any directional letters in its design. Just a pole and a sock are enough to make one.
The purpose of a windsock isn’t to determine the wind direction but rather to help assume the wind speed. Depending on how much the sock is inflated, you can get an idea of the velocity at which the wind is blowing.
Very good use of windsock is the playing ground for badminton or a golf course where the wind speed can mess with the course of a game.
Digital Wind Vane
These are the modern cousins of the old “analog” weather vanes. They share many similarities in design and purpose with the former being more complex and sophisticated. The most apparent difference in their designs is the inclusion of an anemometer in the digital wind vane.
We can assume from the name that a digital wind vane isn’t just an arrow with a vertical pole. Apart from determining the wind direction, you can also use it for measuring wind speed (with the anemometer), atmospheric temperature, humidity, atmospheric pressure, and more. Of course, the weather vane has to have the necessary devices installed on it.
All these features make it a perfect weather station. Since the weather vane is usually installed on top of a building, it makes it the best option to install an anemometer. It’s the same with temperature since it’s positioned high enough to be not obstructed by any structures that can affect the reading.
Most weather vanes in the market are digital. That being said, the complexity of it makes it an unsuitable option for most people.
Most Common Application of a Weather Vane
Weather vanes have only one job. It’s to point us towards the direction of the wind. That would be a false statement in today’s context.
Although wind vanes, for centuries, have helped us by giving the wind direction, now it has many more duties to pull off.
Now, a wind vane is almost always paired with an anemometer to measure the wind speed. Not only that, but the modern weather vanes also help us to utilize wind power by using wind turbines.
Yes, wind vanes now have a more important job. A wind vane can have a positive effect on the efficiency of a wind turbine.
How Do Wind Vanes Help a Wind Turbine?
The issue with a wind turbine is that wind doesn’t always blow in the same direction. In such cases, so much potential energy is lost. How do you take advantage of all the available wind in a 24/7 manner?
Well, you use a weather vane! By integrating a weather vane design, you can adjust the direction of the turbine whenever the wind changes direction. In this way, the turbine will always face the wind.
The design is simple. In the traditional design, we have a tail and a head. To integrate a wind vane into a wind turbine, we just use the blades of wind turbines in place of the head.
So, whenever the tail is forced to move, the blades of the wind turbine will change their direction accordingly.
- When the wind changes direction, the weather vane detects it
- Then, it sends the info to the direct-drive Yaw system
- Yaw drive re-orients the turbine blades in the right direction
- The anemometer measures the wind speed and sends data to the controller
There is so much research going into this design. For instance, nowadays, there are wind turbines that have adopted the weather vane’s wind catching idea and revolutionized it.
Here are some of the established ideas in work,
- Fixed blade wind vanes
- Rotary blade wind vanes
- Hybrid wind vanes
What Is the Best Place to Put a Weather Vane?
We know weather vanes placed on top of houses, cathedrals, barns, and school buildings. Apart from those another common spot for placing weather vanes is the garden since they usually have an open and large space.
It all comes down to where the wind can be experienced the best. So, open space at a good height is the optimum spot to install a weather vane.
What Do the Animals Mean on a Weather Vane?
We all have seen silhouettes of different animals on top of weather vanes. Are there any meanings to them? Or is it all for ornamental purposes?
There are many instances where a specific animal or a person can signify a meaning. For example, the fish-designed weather vane on the Old Billingsgate is an indication of the place. The place is an old fish market, and it has hosted market stalls since the roman era.
A similar market-themed weather vane can be found on top of the rookery hotel in Clerkenwell in London.
Another favorite symbol used on many wind vanes is the symbol of a ship. You can observe one on top of the church of St Nick. It is supposed to symbolize the Christian journey. For clarity, not all of the ship-themed vanes are related to Christianity.
Frequently Asked Questions
Do weather vanes attract lightning?
No, contrary to what you may have thought, weather vanes do not attract lightning. Or at least it is not observed to do so. Even a TV antenna is more of a target for lightning.
What are old weather vanes worth?
Ornamental weather vanes of the old are included among the most precious objects. Even typical but old weather vanes can be worth $15,000. The 19th-century Cow weather vane is a mentionable example.
Other forms of animal weathervanes are also sold for a price between $5,000- $20,000. Prices depend on the material as well as the condition it was found in. Restored pieces aren’t worth the same.
What are old weather vanes are made of?
We can find weather vanes made of different types of metal such as tin, iron, copper, and even bronze. Some were made with wood also.
Does a Weather Vane Need to be grounded?
No, you don’t have to ground a weather vane. If you have a bonded system for the whole building, then you should have your weather vane to it. But without a complete bonded system, DO NOT ground the weather vane. You’ll only increase the chances of lightning strikes.
Who made the rooster design on weather vanes famous?
It was Pope Nicholas in the 9th century who made it compulsory to display the rooster on top of the churches. The intention was to symbolize it as the betrayal of Peter. So the churches put the rooster as the design of their weather vanes.
There you go! This is a complete guide to understanding how weather vanes work and the different variations currently available.
A simple weather vane made over 2,000 years ago has gone through a lot of upgrades and changes. It isn’t just ornamental.
And somehow, instead of fading away, it just got more relevant and worked as a foundational idea behind other inventions to come into the scene.